The present invention relates to a ceramic member used in ion flow control heads, encoders, scales, and high-precision minute electric field shutters.
A ceramic member comprising a thin plate having a plurality of minute throughholes supported by a rigid plate has been used in location detecting devices or recording devices as the parts of ion flow control heads, encoders, scales, and high-precision minute electric field shutters.
In the applications mentioned above, the minute throughholes are used for detecting or recording locations by passing or not passing a gas, liquid, solid particles or light.
For example, when the ceramic member is used as the part of an ion flow control head, as shown in FIG. 3, an electrode 1 is provided on a surface, a dielectric drum 6 is installed on the side where a rigid plate 9 is present, and an ion source 5 is installed on the other side. As a result, the discharge of ions 2 through the minute throughholes 4 is inhibited by making the electrode 1 carry a charge of the same sign as the ions carry. By contrast, ions are allowed to discharge by making the electrode 1 carry a charge of the opposite sign from that the ions 2 carry.
In either use, it is preferred that the drum 3 or the dielectric drum 6 contacts tightly with the opening of the minute throughholes from the point of view of fluid discharge, fluid control, or transfer properties.
However, when conventional ceramic members are used in a high-precision electric field shutters and the like, the presence of a rigid plate 9 interferes with the access of a drum and the like to minute throughholes 4, preventing the drum and the like from contacting the opening. If the drum is made to contact with the opening from the thin plate side, the electrode wiring contacts with the drum causing the electrode to wear, and the electric field cannot be applied to ions effectively because the electrode is apart from the ion source.
Preferably the thickness of the thin plate 13 is small so that the resistance for passing particles is decreased and drum shape followability is improved. However, if the plate is made to thin, the strength of the thin plate 13 is reduced, the adhesion of the drum to the minute throughholes deteriorates due to the deformation of the thin plate 13 to the opposite direction when the drum is approached, or the thin plate 13 is broken when the drum is contacted.
Therefore, it is the object of the present invention to 25 provide a ceramic member which is well adhered with the drum and the like, and does not break due to the contact with the drum and the like.